It is known to mount one or more electrical connectors on a backplane. With such an arrangement, each connector accepts a circuit board having a set of signal receptacles. Each connector typically includes a set of electrical pins (sometimes referred to as "male pins") designed to mate with the electrical receptacles when the circuit board is mounted in the connector. The connector pins are further coupled to a printed wiring board "PWB") mounted on the backplane. The arrangement of signal receptacles, connector pins, and PWB thus cooperate to electrically couple the circuit boards when they are mounted in the connectors.
In the past, such backplane arrangements have used the PWB to distribute power to boards. With this arrangement, the PWB delivered power to a predetermined electrical pin in the connector which, in turn, made contact with the power receptacle when the circuit board was mounted in the connector. As a result of this approach, however, the PWB required heavy copper planes to carry the power, thus increasing the cost of the PWB.
Also as a result of this prior approach, the power layer was forced to be dangerously close to signal layers on some complex PWB layouts, thus creating a risk of electrical short circuits and fire hazards.
Further, the prior approach resulted in a power distribution system that was inefficient. This was because the PWB power layers dissipated a significant amount of power, thus causing substantially reducing the power available to the circuit boards.
Moreover, the prior approach resulted in a power bus that was noisy. This was because the PWB power layers included substantial capacitance and inductance, thus resulting in a high-impedance power bus which, as is known, is inherently noisy at high frequencies.
As a result, there is disclosed a novel arrangement of a backplane with signal bus, which is believed to represent a substantial improvement over the prior art.